1. Field of the Invention
This invention relates to improvements in a surveying system for making a survey by operating a surveying machine by remote control.
2. Description of the Prior Art
A surveying system for making a survey comprises, for example, a surveying machine which is disposed at a reference point, and a reflecting mirror (e.g., a corner cube) as a collimation target which is disposed at a target point collimated by the surveying machine. Generally, the surveying machine used for the surveying system is to process a surveyed distance and a surveyed angle electrically. There are a manual operative type of surveying machine, an automatic surveying machine driven by a motor so as to be rotated horizontally and vertically, an automatic tracking type of surveying machine which has a function of projecting a beam of scanning light and tracking a reflecting mirror as a target point, and the like.
In a survey, there are a case in which a collimation target is caused to coincide with a target point collimated by the surveying machine and a case in which the surveying machine collimates the collimating target disposed at the target point. In these cases, some surveying machines include a point setting device in order that an operator at the target point can discern the surveying machine disposed at a reference point. The point setting device emits point setting beams of light each of which has a different luminous color depending upon right and left positions (or up, down, right, and left positions), or a middle position, so that a direction in which the surveying machine collimates can be indicated roughly.
In a survey made by the manual operative type of surveying machine, an operator on the side of the reference point operates the surveying machine and searches the reflecting mirror as the collimation target disposed at the target point In the case in which the collimation target is caused to coincide with the target point collimated by the surveying machine, a survey is made while an operator on the side of the surveying machine is communicating by wireless with an operator on the side of the collimation target, or rough positioning is first made by the point setting beams of light and thereafter a survey is made while the operators are communicating by wireless with each other.
Likewise, in the case of the automatic surveying machine, almost the same collimating operation is performed as in the case of the manual operative type machine. However, in addition, the automatic surveying machine can be operated by radio or the like from the side of the target point by using the point setting beams of light. In the automatic surveying machine which is provided with a guide laser device for projecting a guide laser beam which is coincident with the collimation direction, the target point can be caused to coincide with the collimation target. Therefore, the operator is not necessarily required to be stationed on the side of the surveying machine. A surveying system by the use of this automatic surveying machine is shown in FIG. 10.
In FIG. 10, reference character 1 denotes a surveying machine, 2 denotes a telescope portion, and 3 denotes a wireless communications apparatus. The surveying machine 1 is laid on a reference point A. The surveying machine 1 emits a beam of light P1 which is used for measuring a distance at a target point B. A collimation axis; of the telescope portion 2 is made coaxial (or parallel) with the distance-measuring light beam P1. The surveying machine 1 is capable of measuring a horizontal angle and a vertical angle with a zero position, and has an automatic rotational mechanism by which the rotation in horizontal and vertical directions can be made automatically (with respect to a detailed construction of the automatic rotational mechanism, see Japanese Patent Application No. Hei 4-131078, for example). Herein, the rotation in the horizontal direction means that the rotation is made on the horizontal plane, and the rotation in the vertical direction means that the rotation is made on the vertical plane.
A pole 4 is stood at a target point B. A reflecting mirror 5 is attached to the pole 4 and, in addition, a wireless communications apparatus 6 and a control device 7 having a memorizing function are attached thereto. The reflecting mirror 5 disposed at the target point B is made coincident with the collimation axis of the telescope portion 2 of the surveying machine 1, and thereby the distance and the angle from the surveying machine 1 to the target point B can be measured by the surveying machine 1. The control device 7 is used for controlling the surveying machine 1 via the wireless communications apparatus 3. 6 and, in addition, for recording and reading the result of measurement made by the surveying machine 1 on the side of the target point B. The automatic cracking type of surveying machine enables labor saving in comparison with the aforementioned automatic surveying machine. That is, the collimation target is caused to roughly coincide by, for example, the point setting device, and thereafter the reflecting mirror of the target point is located by the scanning light emitted from the tracking type of surveying machine for collimation.
The point setting beam of light is used to cause the collimation axis of the telescope portion 2 to coincide with the reflecting mirror 5. Thus, it is preferable to lay the telescope portion 2 of the surveying machine 1 substantially within eyeshot. However, in a case in which a distance from the reference point A to the target point B is too long to discern the telescope portion 2 of of the surveying machine 1 with the naked eye, it is impossible to predict which direction the point setting beam of light will reach the target point B from. This makes it difficult to cause the collimation axis of the telescope portion 2 to coincide with the reflecting mirror 5.
A surveying system by the use of the tracking type of surveying machine has a great advantage in a case in which a plurality of predetermined target points B are repeatedly measured with the condition that obstructions do not lie between the reference point A and the target points B and that the pole 4 erected at the target point B is moved slowly. On the other hand, this system has a disadvantage in a case in which a plurality of target points are marked and in a case in which the pole 4 is moved. The reason is that the reflecting mirror must be automatically tracked. Therefore, if the travel of the tracking beam is obstructed by the passage of vehicles or persons between the reference points A and the target points B or if the travel thereof is obstructed by obstructions, such as trees or buildings, when the pole is moved to change the position of the target point B, the automatic surveying machine will lose sight of the reflecting mirror 5. As a result, the automatic surveying machine has a reflecting-mirror search mode (a mode of searching for a reflecting-mirror) in which the automatic surveying machine searches a very large range. Accordingly, much time is required to search the reflecting mirror 5.
Likewise, in a case in which the automatic surveying machine is controlled by sending out or receiving an operation starting or stopping signal by means of a wireless wave P2 by the use of the wireless communications apparatus 3, 6, it is difficult to cause the collimation of the telescope portion 2 to coincide with the reflecting mirror 5 when the distance from the reference point A to the target point B is too long to discern the surveying machine 1. Additionally, the frequency and output power of the wireless communications apparatus 3, 6 are required to be varied in every country in the world because each country has its own regulations on the wireless wave P2.